Process of insulating electrical conductors.



UNITED STATES; PATENT oFFro GEORGE RUPLEY," or. SOHENEC ADKNE YORK, AssIeNoR To GEN- ..ERAL. ELECTRIC ooMPANY, -A coRPoRAT oNoF NEW YORK.

i PRoo ss INSULATING ELECTRICAL cououcross;

No.806,577. i"

To all whom} it may concern:

Be it known'that I, GEORGE H. RUPLEY, a

. citizen of the United States,.residing at Schen- Qectady, in the county of Schenectady and State of New York, have invented certain new and useful Improvements in Processes of Insulating Electrical Conductors, of which i the. following is a specification.

This invention relates to the insulation of metal, employed in electrical appliances. It finds s ecial application'i-n insulating wire, but is a so useful in other ways,such, for in- 4 stance, as coating 'thecore-laminations of water transformers. The process forms on the sur-l face of the wire or other metal article a thin,j tough, elastic, firmly-adherent film, which is roof, has high dielectric properties, is infus i le at all temperatures to which it is eX- posed in service, is not inflammable, does not.

ow under pressure, and does not crack or "scale off when the wire is bent even on a,

tion, filed December 16, 1902, Serial No.

present invention brings about this result.

entirely successful in practice; but for some classes of work it'has been found desirable to increase the rapidity of hardening, and my My invention therefore relates to a modification of the above-noted method of preparing the coating material whereby it is caused to harden more quickly, as hereinafter set forth and more particularly pointed out in the claims.

The process as heretofore carried on consists of miXin a suitable quantity, according to the bulk o the product required, of commercial linseed-oil with a small quantity say about two per cent.of oXid of zinc and a substantially similar quantity of oXid of lead, (litharge) The mixed mass is raised to a temperature of from Oto 600 Fahrenheit and the heat continued until the oXids are entirely taken up by the oil and the required degree of distillation eifected. A partial saponificatio'n of the oil is thereby caused, the glycerids are broken up, and the glycerin and other elements of the oil driven off. An application of the heat for ten or fifteen hours I Specification of Letters Patenit. Application filed March 1, 1905. 'Serial No. 2e="7,89 8

The process therein; disclosed is- Patented Dec. 5, 1905-.

has been found, to yield satisfactory results ingetting rid by distillation of glycerin and other compounds which prevent the hardening of the film. When the mass requires a good degree of stiffness, about twenty five per cent. of a refractory solvent, such as rosinoil, is added and the mass allowed to cool. The fluid is applied totlie conductor in the manner described in the patent to Clark and Ru ley, No. 687,517, November 26, 1901, an hardened by the, application of heat.

It has been found that the insulation will harden more rapidly by alternately boiling by the process above noted with a quantity of solvent, such as rosin-oil, and it is this process which constitutes my present invention. stifi viscid mass above noted is boiled with a suitable solvent-say rosin'oil ,the amount being about twenty-five per cent. of the re-. siduum. The oil acting as a fluxjrenders the mass liquid. 'The boiling is then continued at the same high temperature until the mass "again becomes 'viscid, when a further addi-.

tion-of rosin-oil or the like is made, this time using about ten per cent.- of oil. The boiling is renewed until the residuum again becomes thick and elastic, but not so sticky as the mass previously produced. This alternate fluxing and boiling operation may be repeated as often as thought desirable. The

l effect is to produce a residuum which when dissolved in rosin-oil, coal-tar oil, turpentine, or other suitable solvent possesses a most eX- traordinary capacity for rapid hardening under heat. The speed obtained by this process is from fifteen to twenty-five feet per minute, which is much faster than was possible in my former process. Moreover, the hardening may be carried on at a somewhat lower temperature by. the use of this process.

I believe that the increased-speed of hardening and the ease with which the film hardens under the preliminary treatment herein described is due to the prolonged boiling which the addition or the repeated addition of the flux permits without destroying the solubility of the product and the facility of applying it to the wire. I believe the prolonged boiling more efiectually breaks up the separation of glycerin, and thus work is done in the preliminary preparation of the mateand fluXing the stifi elastic residuum obtained The oil having been reduced to the glycerids and results in a more thorough rial which would otherwise have to be done on the film after its application to the wire.

What I claim as new, and desire to secure by Letters Patent of the United States, is

1. The process of insulating an electrical conductor which consists in subjecting an oil to alternate thickenings and fluxings, applying a film of the final solution to the conductor, and hardening the film.

2. The process of insulating an electrical conductor which consistsin subjecting a vegetable oil to alternate thickenings by heat and fiuxing with a suitable solvent, applying a film of the final solution to the conductor, and hardening the film.

3. The process of insulating an electrical conductor which consists in alternately thickening linseed-oil by heat and dissolving in an oily flux, applyinga film of the final solution 010 a conductor, and hardening the film by eat.

4. The process of insulating an electrical conductor which consists in producing an elastic residuum by subjecting a quantity of vegetable oil to alternate thickenings by heat and thinnings with an oil flux, dissolving said residuum in a volatile solvent, applyin a film of said solution to said conductor, an hardening said film by heat.

5. The process of insulating an electrical conductor which consists in boiling a quan tity of vegetable oil to an elastic residuum and adding a refractory solvent, reboiling and adding a smaller quantity of the solvent, again boiling and dissolving the residuum thus formed in a more volatile solvent, ap-

plying a film of the solution to the conductor, and hardening said film by heat.

6. The process of insulating an electrical conductor which consists in mixing an oxid with a vegetable oil, producing an elastic residuum from the mixture by alternate thickenings and fluxings, dissolving said residuum in a suitable solvent, applying a coatin of said solution to the conductor, and har e11- ing the coating by heat.

7. The process of insulating an electrical conductor which consists in mixing an oxid with a vegetable oil, boiling the mixture to a thick residuum and adding a refractory solvent, reboiling and adding a less quantity of the solvent, again boiling and dissolving the residuum thus formed in a more volatile solvent, applying a film of the solution to the conductor, and hardening said film by heat.

8. The process of insulating an electrical conductor which consists in mixing linseedoil with metallic oxids, boiling the mixture to a thick, elastic, residuum and adding a quantity of rosin-oil, reboiling and adding a less quantity of said oil, again boiling and dissolving the residuum thus formed in a volatile solvent, applying a film of the solution to the conductor, and hardening said film by heat.

In witness whereof I have hereunto set my hand this 25th day of February, 1905.

GEORGE H. RUPLEY. 

